Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/4a877433e0a7
Author: Zibi Braniecki <zbigniew.braniecki@gmail.com>
Desc: Merge pull request #25471 from zbraniecki/1088364-remove-mozl10n-localize-in-bluetooth

Bug 1088364 - Remove use cases of mozL10n.localize from Bluetooth. r=ianliu

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https://hg.mozilla.org/integration/gaia-central/rev/50ee8ea2ed42
Author: Zbigniew Braniecki <gandalf@mozilla.com>
Desc: Bug 1088364 - Remove use cases of mozL10n.localize from Bluetooth
Bumping manifests a=b2g-bump